Dali, Focal, KEF, and I’m sure plenty other brands make 4-way speakers. They’re typically made by taking a 3-way speaker and adding a subwoofer (like Focal does in Grande Utopia which has 6½ inch midrange, 11 inch midwoofer and a stonking big 16 inch sub), or an ultrasonic tweeter (like Dali does, but they call them 3½-way, also Sony and KEF).
I guess you can make a 5-way by adding both.
I disagree with regards to sampling rate. If you have 44.1 kHz sampling rate, you need a brickwall low pass filter that goes -96 dB between, say 18 kHz and 22.05 kHz to avoid aliasing on audible range (as per Shannon-Nyquist criterion.
That’s -331 dB per octave. A ridiculously high requirement.
Compare that with 96 kHz, which requires -68 dB per octave or 192 kHz which needs -40 dB per octave and higher sampling rate starts making sense.
Rip to any lossless format and you’ll be fine. You can always transcode to another more efficient format if one appears.
In a perverse way, it’s true that even lossless music ages. Namely, if you ripped your music collection to flac twenty years ago, you can probably transcode to flac now and end up with 30% smaller files because encoder efficiency improved over the years. But of course, it’s still bit perfect, even if it’s simply stored inefficiently.
The funniest bit is that those bespoke systems have one manufacturer, but are just premium branded, just badge engineering.
An excellent example that I’m aware of is PSA (Peugeot and Citroen) where the Hi-Fi option was cobbled together from different parts, like head unit from Magneti Marelli, Bosch or Harman, amplifier from a number of different manufacturers and speakers usually from JBL, all branded as a single Philips (in Germany and sometimes the Netherlands), Denon (in Germany and some other markets) or JBL (default in most markets).
So if you don’t like our don’t appreciate one brand’s credentials as sufficiently Hi-Fi, just get your car in a different market.